The project is intended to develop new instrumentation and methods, and to improve existing instrumentation and techniques, for the characterization of biological macromolecules and the study of their interactions. Analytical ultracentrifugation, the techniques ancillary to it, and methods of data analysis using mathematical modeling appropriate for these techniques are the major areas of interest. Studies have continued on the application of mathematical modeling to problems of ultracentrifugal analysis, and on the development of new methods of performing experiments and analyzing data. In particular, a major breathrough in the analysis of protein-nucleic acid and protein-protein interactions has been achieved by devising a new method of performing experiments and analyzing data.